Ref : HostAP IAPP Code

>> I believe IETF is currently working on this area. Which protocol to use
> would also depend on what you are trying to do and what kind of
> expectations there are about interoperability with other implementations
> and likelyhood of the chosen protocol being in use at some point in the
> future.
>
See the CAPWAP charter (1). I'd also recommend that you keep track of
the future IEEE 802.11v and 802.11r.
(1): http://www.ietf.org/html.charters/capwap-charter.html